Quartz, the macro-crystallized form of silica, is one of the most common mineral specimens. Its clear beauty, combined with the occasional prism effect, makes them highly sought after despite its almost constant appearance in the Earth’s crust. Some people like to take their appreciation to the next level, creating great display specimens with a little bit of manual labor.
So, let’s forge ahead and I’ll teach you how to cut and polish quartz crystals to create great specimens!
Should You Cut and Polish Your Crystals?
This is a personal call, and one that has to be made with each individual specimen. The majority of people prefer their quartz to have a natural surface so polishing can affect the value if you’re looking into resale.
On the other hand, a bit of elbow grease can turn a subpar specimen into a fantastic one.
And not all quartz that has a high value is necessarily attractive. Personally, I find some formations like elestial quartz to be unsightly, but I won’t cut and polish them since it will destroy the heightened retail value of the formation.
If you’re selling crystals, then I suggest taking a look over some of the forms associated with metaphysical use before making the decision to cut anything that may be more “interesting” than “beautiful.”
In the end, it’s a personal call, but some formations that aren’t necessarily appealing are still worth a lot of money to the right person.
As a general rule, I only polish quartz with interesting inclusions to get a better view of them, but everyone will have their own taste in the matter.
- Druzy Quartz (What Is It and How Does It Form?)
- Ultimate Guide To Collecting Quartz (What It Is and How To Find It)
How To Cut and Polish Quartz Crystals
What You Need
You’re going to need a few things to do this right. There are a few different phases that we’re going to go through as we clean, cut, and polish these crystals and you may not need to go through all of them.
For basic cleaning, I suggest:
- Dawn Dish Soap
- Stiff Sponge or Scrub Brush
- White Vinegar
- Wire Brush (Brass preferred, but steel works as well)
These will handle most of the basics when it comes to cleaning.
Some specimens will need to be processed further to remove unsightly stains. These mostly include manganese and iron on quartz specimens, which appear as reddish, blackish, or orangeish stains on the crystals.
We’ll be using some form of oxalic acid to remove them. I prefer to use a powdered form and Iron Out is a good brand. A respirator and gloves are required to work with acids, make sure you have them.
For actually cutting the specimen, such as removing a point from a cluster, you’ll need some form of trim saw. You can use a tile saw in this case but you also need the right blade.
- Tile Saw– This saw is sufficient, but not ideal. The included blade is not ideal for quartz, and may not work at all on bigger pieces.
- 4” Diamond Blade– There are cheaper options than the one linked, but I can attest to this blade working well with quartz crystals. Cheaper blades may bring their own problems.
And finally, you’ll need polishing supplies. Polishing quartz crystals by hand is a fool’s errand, so you’ll need the following:
- Sandpaper- To smooth any surfaces which have a lot of variation in height
- Cerium Oxide Powder- To make the polishing paste once you reach this stage.
- Rotary Tool or Grinder – Felt wheels are preferred, leather or cotton will also work if that’s all you have.
So, now that you have everything together… it’s time to begin!
1. Clean the Crystal
Quartz crystals usually have a bit of clay or dirt trapped on the exterior. You’ll need to remove this before you can go any further along in the process.
Get a bucket or bowl that can fit your crystals comfortably and add water and a few drops of Dawn. You don’t need an overly soapy bucket, just enough soap to break up any organic residue and float dirt particles off the surface.
Use the sponge first, then upgrade to the wire brush if softer methods won’t remove all of the material. Once you’re done, get a jar or other container that can easily be closed for the next step.
2. Gentle Chemical Treatment
Take the cleaned quartz and stick it in white vinegar, no water added.
Vinegar will take care of calcium stains from tap water, any calcite or limestone stuck on the exterior, and a few other light stains that won’t be removed with just water and soap.
Soak the quartz for at least an hour and up to 24 hours. Silica is completely impervious to acetic acid, so there’s no risk to your crystals.
Once you’ve finished, check the crystals for staining that may need to be removed with harsher chemicals.
3. Remove Metallic Oxides With Acid
Iron Out, or any form of oxalic acid, will make short work of the majority of metallic stains on your quartz. Handling it is more of a problem than actually using it.
Use all appropriate safety gear when working with acids. Goggles, mask, and gloves. It’s not worth the risk to save a few seconds donning PPE, especially since the process takes some time.
The usual concentration with powdered forms of oxalic acid is 1 tablespoon per pint of water. Carefully measure so that you have a solution that is over the top of the crystals in a glass or plastic container.
Soak them, you can check after 20 minutes and find them gone in some cases. In others, you may need up to 24 hours.
Once the stains have been removed (or mostly removed), you can take the specimen out and neutralize it in a baking soda and water solution. Neutralize and dispose of the remaining acid in accordance with local regulations (usually just taking it to the dump as HAZMAT).
Attack any remaining oxides with the brush, most will come off readily. If the specimen is highly stained you may need to go after it more than once with the Iron Out.
4. Trim to Your Liking
If you need to trim the specimen by removing other pieces of the cluster, large protruding pieces of stone, or otherwise massively alter the exterior you’ll need to fire up the saw.
Use the saw carefully, and keep your goggles on. A flying quartz shard can be very dangerous and the material is prone to conchoidal fractures that send pieces out unpredictably.
You can also use the side of the blade as a sort of crude grinder if you have any sides that are particularly rough.
Once trimmed to the final shape, you’re ready to polish!
5. Sand the Surfaces
Most people will want to polish the sides along their natural crystalline planes. This is easy enough, just use sandpaper in the 400-600 grit range to start with.
Backing the paper with a piece of glass or another very flat surface will allow you to get clean sanding on the sides and any termination faces that you’re working with. Continue working with successive grits of sandpaper until you reach at least 1000 grit, but preferably keep moving to the 2500-3000 range for the highest clarity.
Quartz works very slowly when you work by hand. As a general rule, any hand work on quartz is going to take at least as long as doing the same with an agate. To keep sharp edges you need to work each face of the crystal separately.
Always wet sand your quartz. It’s not worth trying to do it dry and spreading the dangerous dust even more. Make sure your mask is on properly during this process, and that you’re paying attention to the mud that forms. The mud will get more opaque as you lose water, and you should dip the stone again when it gets milky white.
Any curves or changes in direction you make can cause the edges of the crystal to be rounded. It’s a “nice” aesthetic, but it’s usually best to just create sharp planes to preserve the integrity of the crystal.
You can also use a flat lap for this step if you have access to one, and go through roughly the same grit progression using wheels and diamond paste instead.
After you’re happy with the surface finish’s sanding, you can begin the actual polishing process.
6. Final Polishing
Take some of your cerium oxide powder and mix it with a bit of water in a small container. This will form a paste you can pick up with your preferred polishing method.
If you’re using a rotary tool, the key is to charge the wheel periodically and use a slow, small, circular pattern to cover the surface. Do it repeatedly on each surface, trying not to go over the edge of the crystal planes to avoid rounding them out.
On a proper polishing wheel, it’s just a matter of moving it back and forth while doing your best to avoid rounding out the corners. Use a tight grip on the stone but light pressure on the wheel.
If your grip loosens too much the wheel is going to throw the stone, which usually ends in a disaster. If you put too much pressure it also has a higher chance to grab, with the bonus of causing the entire crystal to heat up quickly.
Check for scratches after the first serious round of polishing. If there’s anything significant you may need to re-sand that crystal face for the best end result.
This will take a bit of time, but once the quartz is to your liking… well, you’ve just polished your first specimen! Be careful, it can be a bit addicting.
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